Various designs of micromechanical systems capable of light diffraction have been previously developed for a number of applications. One class of micromechanical diffraction elements, the grating, can be used for various electro-optical applications such as spectroscopy or as spatial light modulators for applications such as display technology and optical signal processing.
A spatial light modulator is presented in U.S. Pat. No. 5,061,049 whereby a reflective element is electrostatically controlled by electrodes to achieve various angles of beam deflection. The primary advantage taught in this patent is the small deflection angle and uniform beam deflection achieved by using two sets of electrodes designated address electrodes and landing electrodes. The landing electrodes minimize the stress to the deflected element. The simple design of the reflective element provides ample means of beam deflection but does not address the diffraction requirements of spectroscopy.
A deformable grating apparatus is presented in U.S. Pat. Nos. 5,459,610 and 5,311,360 both by Bloom et al. The grating apparatus is presented as a means to modulate incident light rays primarily for display technology applications. An array of beams, at initially equal heights and with reflective surfaces, are supported at predetermined fractions of incident wavelength above a similarly reflective base. Below the base is a means of electrostatically controlling the position of the beams by supplying an attractive force which will deflect all of the beams or every other beam to a secondary position. The diffraction of the incident light is dependent upon the position of the reflective beam elements. The primary application of the grating apparatus presented in these prior art patents is as a spatial light valve. Control of the deformable grating apparatus is limited for spectroscopic applications.